Switch construction



Nov. 12, 1957 v R. B. sElDEL ETAL 2,813,165

SWITCH CONSTRUCTION Filed May 25, 1954 T1 E.. Q Z8 0 52 www n1 Q ma 20 United States Patent() SWITCH CONSTRUCTION Robert B. Seidel, Hamden, and Rudolph Anthony Vermella, `New Haven, Conn., assignors to 'Safety Indus- .tries,-Inc., New Haven, Conn., a corporation of Dela- -WBI Application 'May 25, 1954, Serial No. 432,212

3 Claims. (Cl. 20o-87) Y'1I`hisinvention relates to a switch construction and more particularly to an electromagnetica-lly operated make-and-break switch of the circuit breaker type.

.One of the objects of this invention is to provide a switch construction whose simplicity of design willreadily lendfitself to economical manufacture and reliable operation. Another object is to provide aswitch construction of. the above character which Vmay be made from inexpensive materials without sacrificing durability and reliability. Another object is to provide a switch construction of the above character whose operation makes 'for a clean makeand-break substantially free from arcing and Vhence responsible for increased periods of operation without repair or maintenance.

Switches of the make-and-break or circuit breaker type have :been notoriously cumbersome in construction requiring expensive specially made parts and complex assembly operations during manufacture. Not only were the designs of such vswitches responsible for difficulties in manufacture, thus increasing costs substantially, but they also led to unreliable operation. This was particularly due to the action of the switches in engaging and disengaging the contact buttons in such manner as to promote excessive arcing, lrubbing and rolling, all of which actions led -to excessive wear and tear on the contact buttons. Accordingly, such switches demand constant attention and maintenance coupled with frequent repair such as replacement of contact buttons etc. It is a further object of the present invention to provide a switch Whose construction is such that it will readily obviate the above and other difficulties.. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts, which will be exemplitied in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims to follow; for a fuller understanding of the nature and objects of the invention, reference should be had to the lfollowing detailed description taken in connection with the accompanying drawing, in which:

Figure 1 is a side elevation of the switch in open position.

Figure 2 is a side elevation similar to Figure l but with the switch in its closed position.

Figure 3 is a vertical sectional view taken along the lines 3-3 of Figure 2.

Figure 4 is a fragmentary, diagrammatic view of the switching elements in the open position and on the way to the closed position, and

Figure 5 is a diagrammatic view similar to Figure 4 with the switching elements in closed position.

Similar reference characters refer to similar parts throughout the several views of the drawings.

The construction and operation of our make-and-break switch may be very generally described by reference to Figure 1 wherein a base generally indicated at 10 preferably formed from any suitable dielectric material has 2,813,165 Patented Nov. 12, 1957 extending therefrom a fixed contact member generally indicated at 12. Below fixed contact member 12 is an L-shaped magetic iron core generally indicated at 14 also secured to the base 10 and extending therefrom. A coil generally indicated at 16 is mounted on the core 14 and an L-shaped armature yoke generally indicated at 18 is pivoted to the lower end of the core with its vertical leg portion 20 facing the end of the core. The armature yoke 18 is limited in pivotal movement by a bracketpiece generally indicated at 22 secured to core 14 which also holds coil 16 in the position shown. An adjustable'bolt generally indicated at 24 is slidably mounted in bracketpiece 22. A spring contactor generally indicated `at 26 is secured to armature yoke 18 and carries a contact button 28. Accordingly, when coil 16 is deenergized armature yoke 18 is in its lower position with contact button 28 disengaged from fixed contact 12. However, when coil 16 is energized armature yoke 18 is pivoted in a counter-clockwise direction to engage the contacts i. e. to the position shown in Figure 2.

More particularly, as best seen in Figures l and 3, the L-shaped core 14 comprises a series of individual laminations 30 (Figure 3) preferably identical in shape and size and secured to base 10 by brackets 32 and 34, screws 36 and bolts 38. Coil 16 fits around the horizontally extending leg 40 of core 14 and preferably has a square shaped aperature for this purpose. Coil 16 may be connected in circuit for its energization when it is desired to close the switch, thereby creating a magnetic field to attract armature yoke 18 in a manner to be described in greater detail hereafter.

Still referring to Figures l and 3 the U-shaped bracketpiece 22 is made from suitable magnetic material such as steel and has a pair of legs 44 and 46 secured to the end of leg 40 and extending therebelow with its bottom portion 42 spaced therefrom; preferably bracketpiece 22 rests against the adjacent end of coil 16 to hold the coil firmly in position against the vertical leg 48 of core 14. Accordingly, this core 14 having the coil 61 mounted thereon is firmly affixed to the base 10 and the coil is held in such position by bracketpiece 22. The depending legs 44 and 46 and bottom portion 42 of bracketpiece 22 also act as a magnetic shunt to the smaller air gap G to increase the intensity of the magnetic pull on armature yoke 18`thereby reducing the size of the coil required.

Fixed contact member 12 includes the post 50 secured to base 10 in any convenient manner with a contact button 52 on its front end. Contact buttons 52 and 28 are of the conventional type, preferably formed from a silver alloy commonly used in these switches to resist the wear and tear of switch operation.

. A 'fixture 54 is bolted to the lower end of leg 48 and extends horizontally therefrom while the horizontal 'leg 56 of armature yoke 18 has a reduced end 58 pivotally connected to fixture 54 by a `stud 60 or the like. Bolt 24 ex tends through leg 56 or armature yoke 18 and is adjustably locked in `desired position by locknuts 62. As can be seen in Figures l and 3, bolt 24 extends through a suitable aperture in the horizontal 'bottom 42 of bracketpiece 22 so that .the head 24a thereof is located between core 14 and the bracketpiece. Consequently, this head 24a of the bolt 24 acts as Ia stop limiting the pivotal movement of the armature yoke 18 and therefore the size of .the gap between contacts 52 and 28. When coil 16 is deenergized the armature yoke 13 pivots in a clockwise direction by force of gravity to the position shown in Figure 1 with head 24a of the bolt resting on bottom 42 of lbracketpiece 22. When lthe coil is energized to move the switch to the closed position lshown in Figure 2, Ihead 24a preferably occupies a position intermediate bottom 42 and core 14. Armature yoke 18 is Iso shaped with respect to its pivotal point about stud 60 that no additional weight is needed to hold it in the lopen position. This is important for if this switch is mounted on a vehicle Such as a lrailroad car where there is often excessive bouncing when in transit such bouncing will not engage contact buttons 52 and 28.

The spring arm 26 includes two Strips 66 and 68 and interposed therebetween is a heavy braided pigtail or Strand 70; preferably these strips are Phosphor bronze and the strand is copper. i Strand 70 is soldered or otherwise secured to lstrips 66 and 68 at points 26a and 2Gb, su'bstantially at the opposite ends of contacter arm 26. This strand is stretched Ibetween these points so that it is constantly under tension and solidly packed between the two strips to thereby form the unitary spring contactor arm 26. As can be seen in Figures 1 land 2, contactor arm 26 takes the shape of an inverted U with the contact button 28 on its upper -free end facing contact button 52 and with its lower end anchored to the extremity of armature yoke 1:8 by 'a screw 72. Strips 6'6 and 68 are heavy enough to inhibit substantially rebounding and bouncing of the contactor arm 26, but the strand 70, filling the space there between, is responsible for a considerable dampening effect. These two factors serve to eliminate appreciable bouncing which might otherwise result in inadvertent contact engagement or arcing.

Quite aside from bouncing or vibrating, it is most irnportant that the faces 28a and 52a of the contact buttons engage each other in straight line fashion as distinguished from the rolling effect achieved by many makeand-'break switches now in use. This switch is designed so that substantially all relative movement between contact vbuttons 2'8 and 52 at the time of engagement is confined to directions normal to and parallel to surfaces 28a and 52a. `In Figures 4 and 5 the stationary and movable contact members are lshown diagrammatically moving from the open position of Figure 4 to the closed position of Figure 5. Thus with F representing the switch closing force reaction on the moving contact button 28, the moment F11 produces a counter-clockwise torque T1 (indicated by arrow X) which etects .angular movement M1 about points a and f. The moment F12 produces a clockwise torque T2 (indicated by arrow Y) causing angular movement M2 about point a'. The strips 66 and 68 and strand 70 may be so designed that M1 will equal M2 for any switch engaging force. Thus all relative movement between contact buttons 28 and 52 will be rectilinear and along the axis F (normal to the Surfaces 28a and 52a) and along the axis Z (parallel to the 28a and 52a) i. e. a sliding or wiping action. Expressed in vanother way this results in the moveable contact engaging the entire face 52a of the fixed contact instantaneously and simultaneously. Due to the `sliding action along the Z axis practically all arcing is successfully avoided and this also tends to keep the contact surfaces 28a and 52a clean thereby further inhibiting arcing. In practice when all rolling between the contacts is avoided, as is the case here, the moveable contact will not roll lover dirt on the contact faces which rolling action further increases arcing and makes maintenyance of clean contact surfaces practically impossible.

It will accordingly Vbe seen that we have provided a switch which is very simple indesign and hence lends itself to economical manufacture. Further the closing :action including the damping effect of the strand and the rectilinear relative movement of the contact faces when closing reduces arcing to a minimum and consequently serves to make for a very reliable operation. Thus it will be seen that the several objects hereinabove referred to as well as many others are successfully accomplished.

Since certain changes may be made in the construction which has been described without departing from the scope of the invention it is intended that all matter contained in the 4above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

We claim: v

l. In a switch construction, the combination of a ixed contact, a movable contact including la spring member extending toward ,said iixed contact and supporting a contact button opposite said iixed contact, said member comprising spring plates encasing a pigtail of braided copper strands attached to said plates under tension and solidly packed therebetween, and means secured to said movable contact member and supporting it for pivotal movement toward and from said iixed contact.

2. The combination defined in claim l 'in which said movable contact member is in the yshape of an inverted U, one eind of which is anchored to said movable support and the other end of which has secured thereto a contact but'- ton adjacentsaid xed contact. Y

3. -In a switch construction, the combinati-on of a base, a rfixed contact extending from said base, an L-shaped iron core mounted on said `base with a horizontal leg extending therefrom substantially beneath said iixed contact, a coil supported on said leg, an L-shaped yoke member pivotally connected to said lbase withv a vertical leg extending upwardly at right angles to said horizontal leg of said core and facing its end, and a spring piece in the form of 'an' inverted U, said spring piece -comprising a pair of spaced Phosphor bronze Strips having braided copper strands embedded therebetween and fastened thereto, whereby bouncing of said spring piece is inhibited, said spring piece having one end connected to said vertical leg and the other end carrying a contact button facing said xed contact, whereby upon energization of said coil said L- shaped memberis attracted to said core to pivot and move Said contact button into engagement with said stationary contact.

References Cited in the tile of this patent UNITED STATES PATENTS 

